Coordinated motion control of a pneumatic-cylinder-driven biaxial gantry for contour tracking tasks

2017 ◽  
Vol 40 (7) ◽  
pp. 2249-2258 ◽  
Author(s):  
Deyuan Meng ◽  
Aimin Li ◽  
Fei Chen ◽  
Kai Zhang
Keyword(s):  
Robust Control ◽  
Motion Control ◽  
Adaptive Robust Control ◽  
Contour Error ◽  
Pneumatic Cylinder ◽  
Coordinate Frame ◽  
Practical Implementation ◽  
Model Parameters ◽  
Contour Tracking ◽  
Coordinated Motion

In this paper, coordinated motion control of the pneumatic-cylinder-driven biaxial gantry for precise contour tracking is investigated. An adaptive robust coordinated motion controller is developed by incorporating the task coordinate formulation into the adaptive robust control architecture. Specifically, a task coordinate frame is used to approximately calculate the contour error, which is utilized for controller design to generate coordination between two axes. Furthermore, the proposed controller utilizes online parameter adaptation to estimate some important unknown model parameters, and employs a robust control law to attenuate the effects of parameter estimation errors, unmodelled dynamics and external disturbances. Therefore, certain transient contouring performance and steady-state contour tracking accuracy can be guaranteed. Extensive comparative experimental results obtained verify the effectiveness of the proposed coordinated motion control strategy and its performance robustness to sudden disturbances in practical implementation.

Adaptive Robust Control of Circular Machining Contour Error Using Global Task Coordinate Frame

2013 ◽  
Author(s):  
Tyler A. Davis ◽  
Yung C. Shin ◽  
Bin Yao
Keyword(s):  
Robust Control ◽  
Control Problem ◽  
Research Work ◽  
Approximation Error ◽  
Adaptive Robust Control ◽  
Contour Error ◽  
Coordinate Frame ◽  
Tool Deflection ◽  
Machining Processes ◽  
Highly Nonlinear

The contour error of machining processes is defined as the difference between the desired and actual produced shape. Two major factors contributing to contour error are axis position error and tool deflection. A large amount of research work formulates the contour error in convenient locally defined task coordinate frames that are subject to significant approximation error. The more accurate global task coordinate frame (GTCF) can be used, but transforming the control problem to the GTCF leads to a highly nonlinear control problem. An adaptive robust control (ARC) approach is designed to control machine position in the GTCF, while directly accounting for tool deflection, to minimize the contour error. The combined GTCF/ARC approach is experimentally validated by applying the control to circular contours on a three axis milling machine. The results show that the proposed approach reduces contour error in all cases tested.

Adaptive Robust Control of Circular Machining Contour Error Using Global Task Coordinate Frame

2015 ◽  
Vol 137 (1) ◽  
Author(s):  
Tyler A. Davis ◽  
Yung C. Shin ◽  
Bin Yao
Keyword(s):  
Robust Control ◽  
Control Problem ◽  
Research Work ◽  
Approximation Error ◽  
Adaptive Robust Control ◽  
Contour Error ◽  
Coordinate Frame ◽  
Tool Deflection ◽  
Machining Processes ◽  
Highly Nonlinear

The contour error (CE) of machining processes is defined as the difference between the desired and actual produced shape. Two major factors contributing to CE are axis position error and tool deflection. A large amount of research work formulates the CE in convenient locally defined task coordinate frames that are subject to significant approximation error. The more accurate global task coordinate frame (GTCF) can be used, but transforming the control problem to the GTCF leads to a highly nonlinear control problem. An adaptive robust control (ARC) approach is designed to control machine position in the GTCF, while additionally accounting for tool deflection, to minimize the CE. The combined GTCF/ARC approach is experimentally validated by applying the control to circular contours on a three axis milling machine. The results show that the proposed approach reduces CE in all cases tested.

Adaptive robust control of machining force and contour error with tool deflection using global task coordinate frame

2016 ◽  
Vol 232 (1) ◽  
pp. 40-50 ◽  
Author(s):  
Tyler A Davis ◽  
Yung C Shin ◽  
Bin Yao
Keyword(s):  
High Performance ◽  
Milling Process ◽  
Adaptive Robust Control ◽  
Contour Error ◽  
Coordinate Frame ◽  
Tool Deflection ◽  
Peripheral Milling ◽  
Robust Controller ◽  
Control Approach ◽  
Machining Force

Peripheral milling process productivity or quality can be improved by controlling either cutting force or contour error. While each means for improvement is often addressed individually, efforts to control both aspects simultaneously are less common in the literature. This article describes an approach to control both the contour error and force using an adaptive robust controller. The axes dynamic behavior and tool deflection are considered as the two major sources of error expressly considered in the control design and are embedded in a global task coordinate frame representation of contour error. The adaptive control component maintains high-performance control of both force and contour error in the presence of significant model error or external disturbances. The control approach is implemented on a three-axis machine tool for validation. Experimental results indicate that significant improvements to both contour error and force regulation have been achieved.

scholarly journals Simplified Adaptive Robust Motion Control with Varying Boundary Discontinuous Projection of Hydraulic Actuator

2014 ◽  
Vol 2014 ◽  
pp. 1-10
Author(s):  
Cungui Yu ◽  
Xianwei Qi
Keyword(s):  
Robust Control ◽  
Motion Control ◽  
High Performance ◽  
Simple Algorithm ◽  
Adaptive Robust Control ◽  
Hydraulic Systems ◽  
Hydraulic Actuator ◽  
Tracking Accuracy ◽  
Rotary Actuator ◽  
Robust Motion Control

This paper deals with the high performance adaptive robust motion control of electrohydraulic servo system driven by dual vane hydraulic rotary actuator. The recently developed adaptive robust control theory is used to handle the nonlinearities and modelling uncertainties in hydraulic systems. Aside from the difficulty of handling parametric variations, the traditional adaptive robust controller (ARC) is also a little complicated in practice. To address these challenging issues, a simplified adaptive robust control with varying boundary discontinuous projection is developed to enhance the robustness of the closed-loop system, based on the features of hydraulic rotary actuator. Compared with previous ARC controller, the resulting controller has a simple algorithm for more suitable implementation and can handle parametric variations via nonlinear robust design. The controller theoretically achieves a guaranteed transient performance and final tracking accuracy in the presence of both parametric uncertainties and uncertain nonlinearities. Extensive simulation results are obtained for a hydraulic rotary actuator to verify the high performance nature of proposed control strategy.

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